LTC1421/LTC1421-2.5
Hot Swap Controller
U
FEATURES
DESCRIPTIO
The LTC®1421/LTC1421-2.5 are Hot SwapTM controllers
that allow a board to be safely inserted and removed from a
live backplane. Using external N-channel pass transistors,
the board supply voltages can be ramped up at a program-
mable rate. Two high side switch drivers control the N-
channel gates for supply voltages ranging from 3V to 12V.
■
Allows Safe Board Insertion and Removal from a
Live Backplane
■
System Reset and Power Good Control Outputs
■
Programmable Electronic Circuit Breaker
■
User Programmable Supply Voltage Power-Up Rate
■
High Side Driver for Two External N-Channels
■
Controls Supply Voltages from 3V to 12V
Aprogrammableelectroniccircuitbreakerprotectsagainst
shorts. Warning signals indicate that the circuit breaker
hastripped,apowerfailurehasoccurredorthattheswitch
drivers are turned off. The reset output can be used to
generate a system reset when the power cycles or a fault
occurs. The two connect inputs can be used with stag-
gered connector pins to indicate board insertion or re-
moval. The power-on reset input can be used to cycle the
board power or clear the circuit breaker.
■
Connection Inputs Detect Board Insertion or Removal
■
Undervoltage Lockout
Power-On Reset Input
■
U
APPLICATIO S
■
Hot Board Insertion
Electronic Circuit Breaker
■
The trip point of the ground sense comparator is set at
0.1V for LTC1421 and 2.5V for LTC1421-2.5.
The LTC1421/LTC1421-2.5 are available in 24-pin SO and
SSOP packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
U
TYPICAL APPLICATIO
Q3
1/2 Si4936DY
V
EE
–12V
1A
C3
R4
20k
5%
C
C
LOAD
0.47µF
+
+
V
EE
R2
0.025Ω
Q2
1/2 Si4936DY
2
V
DD
1
12V
1A
V
DD
3
4
R1
0.005Ω
Q1
LOAD
MTB50N06E
V
5V
5A
CC
1
2
V
CC
10k
16
+
R6
20k
1%
3
4
22
C
LOAD
C2
23
21
20
19
18
17
D1
0.1µF
R5
16k
5%
V
SETLO GATELO V
V
SETHI GATEHI V
CCLO
OUTLO CCHI
OUTHI
10
9
14
13
8
11
15
6
RAMP
R3
1k
2
24
CON2
AUXV
CPON
–
COMP
COMP
CC
R7
7.15k
1%
C1
1µF
1µF
+
LTC1421
REF
FB
COMPOUT
PWRGD
RESET
4
µP
FAULT
POR
FAULT
I/O
I/O
RESET
3
1
POR
7
CON1
GND
12
DISABLE
5
1
13
12
GND
BEA
BEB
GND
V
CC
DATA BUS
DATA
BUS
1421 TA01
QS3384
QuickSwitch®
QuickSwitch IS A REGISTERED TRADEMARK
OF QUALITY SEMICONDUCTOR CORPORATION.
BACKPLANE
PC BOARD
1